JP5846997B2 - Film forming composition, surface cleaning method, radioactive substance removing method, surface protecting method, and film - Google Patents

Description

  The present invention relates to a film forming composition, a surface cleaning method, a radioactive substance removal method, a surface protection method, and a film.

  A so-called pack cleaning method has attracted attention as a method for cleaning dirty walls and the like. The pack cleaning method is a method in which a film-forming composition containing a film-forming polymer is applied to a dirty wall surface and the film formed by drying the coating film is peeled off from the wall surface. According to this method, the dirt on the wall surface adheres to the peeled film side.

  Although the above-described pack cleaning method sometimes makes it difficult to peel off the film formed on the wall surface, Patent Document 1 discloses a technique for forming a film that can be easily peeled off in the pack cleaning method.

JP-A-10-314688

  If the film forming composition described in Patent Document 1 is used by the method described in Patent Document 1, dirt on the wall surface can be easily removed. However, in the film forming composition described in Patent Document 1, since the main component of the film forming polymer is polyvinyl alcohol, the film has almost no water resistance. For this reason, in order to use this film forming composition outdoors, it is necessary to be careful not to wet the film formed by rain or the like. Moreover, since the film | membrane which contains polyvinyl alcohol as a main component also has the problem that it is easy to tear at the time of peeling, in patent document 1, the multilayer film is formed in the wall surface.

  The film formed of the film-forming composition is often required to have water resistance even for purposes other than those described above. Then, the 1st subject of this invention is providing the film forming composition which forms a film | membrane with water resistance.

  Moreover, when it is a film | membrane formed with the composition for film formation, Comprising: Assuming peeling after film | membrane formation, it is calculated | required that it is a film | membrane which can be peeled easily. Furthermore, in view of the labor of film formation, it is required to realize ease of peeling with a single layer film. Then, the 2nd subject of this invention is providing the technique for forming the film | membrane which can be peeled easily even if it is a single layer and can be used outdoors.

  The inventors of the present invention have made extensive studies to solve the above problems. As a result, the film-forming composition is a liquid containing rubber (A) and polyvinyl alcohol (B), and the content of rubber (A) in this composition is greater than the content of polyvinyl alcohol (B). As a result, the present inventors have found that the above problems can be solved, and have completed the present invention. More specifically, the present invention provides the following.

  (1) A film-forming composition, which is a liquid containing rubber (A) and polyvinyl alcohol (B), and wherein the content of rubber (A) is greater than the content of polyvinyl alcohol (B).

  (2) The film formation according to (1), wherein the content ratio of the rubber (A) and the polyvinyl alcohol (B) is 0.01 to 0.3 in terms of mass ratio ((B) / (A)). Composition.

  (3) For film formation according to (1) or (2), the total of the content of the rubber (A) and the content of the polyvinyl alcohol (B) is 60% by mass or more with respect to the total solid content. Composition.

  (4) The film forming composition according to any one of (1) to (3), wherein the rubber (A) is natural rubber.

  (5) The film-forming composition according to any one of (1) to (4), comprising natural rubber latex.

  (6) The film-forming composition according to any one of (1) to (5), further comprising a water-insoluble powder (C).

  (7) The film-forming composition according to (6), wherein the water-insoluble powder (C) is a powder having a radioactive substance adsorbing ability.

  (8) The film forming composition as described in any one of (1) to (7), which is used for cleaning the surface of a structure.

  (9) The film forming composition as described in any one of (1) to (7), which is used for removing radioactive substances existing on the surface of the structure and / or the ground surface.

  (10) The film-forming composition according to any one of (1) to (7), which is used for forming a temporary surface protective film on the structure surface and / or the ground surface.

  (11) A film forming step of forming a temporary film by applying the film-forming composition according to any one of (1) to (7) to the structure surface, and a peeling step of peeling the film Surface cleaning method provided.

  (12) The surface cleaning method according to (11), wherein in the film formation step, the film is formed as a single layer.

  (13) The surface cleaning method according to (11) or (12), which is applied to surface cleaning of an outdoor structure.

  (14) A film forming step of applying the film forming composition according to any one of (1) to (7) to the structure surface and / or the ground surface to form a temporary film, and peeling the film A radioactive substance removing method comprising: a peeling step.

  (15) A surface protection method for forming a temporary surface protective film by applying the film forming composition according to any one of (1) to (7) to a structure surface and / or a ground surface.

  (16) A film containing rubber (A) and polyvinyl alcohol (B), wherein the content of rubber (A) is greater than the content of polyvinyl alcohol (B), and the thickness of the film Is a film having an elongation at break measured by a method according to JIS K-6251 of 150% or more and 1300% or less.

  According to the present invention, even when a single-layer film is formed on the surface of the structure, the film can be easily peeled off from the surface and collected. In addition, according to the present invention, a water-resistant film is formed on the surface of the structure. Therefore, even if the structure is placed outdoors and the film gets wet with rain or the like, a problem hardly occurs.

It is a schematic diagram which shows the usage method of the composition for film formation of this invention.

  Hereinafter, embodiments of the present invention will be described. In addition, this invention is not limited to the following embodiment.

<Film forming composition>
The film-forming composition of the present invention is a liquid containing rubber (A) and polyvinyl alcohol (B), and the content of rubber (A) is larger than the content of polyvinyl alcohol (B). When the content of the rubber (A) is increased, water resistance is imparted to the formed film. Moreover, when the content of the rubber (A) is increased, the film is easily stretched, and the strength of the film is increased, so that the film is difficult to tear when the film is peeled off. For this reason, even if the film formed on the surface of the structure is a single layer, the film can be easily peeled off from the surface and collected. And by adjusting the adhesion to the surface of the structure with polyvinyl alcohol (B) while adjusting the elongation of the film with rubber (A), it can be sufficiently adhered to the surface of the structure and easily peeled off. A film can be formed. Hereinafter, the components contained in the film-forming composition of the present invention will be described.

[Rubber (A)]
Since the rubber (A) is only required to impart elongation and water resistance to the film, the type of the component (A) is not particularly limited, and either natural rubber or synthetic rubber can be used. Moreover, what was bridge | crosslinked as rubber | gum (A) may be used and the timing to bridge | crosslink is not specifically limited, either. Common components such as a crosslinking agent and a crosslinking aid can also be used.

  Examples of the natural rubber include those obtained by separating the natural rubber from a natural rubber latex liquid collected from a rubber tree represented by heve brasiliensis and forming a sheet, block, powder, or the like. . As long as it is such, it may be smoked and dried, or may be dried without being smoked. The main component of natural rubber is cis-1,4-polyisoprene.

  The molecular weight of natural rubber is preferably distributed in the range of 10,000 to 2,000,000.

  If the rubber (A) is natural rubber, the film is more easily stretched than the synthetic rubber, and it is preferable because the film is not easily broken when the film is peeled off. In particular, when the film-forming composition contains natural rubber latex containing natural rubber, the above-described effect that the film is easily stretched further increases. Natural rubber latex may contain ammonia, and the odor from the film may be a problem, but acid components such as citric acid and formic acid are added to the natural rubber latex and film-forming composition. This problem can be solved easily.

  Moreover, since natural rubber is a plant-derived material, it is preferable in that it does not use petroleum resources and biodegrades.

  Examples of the synthetic rubber include diene polymer rubber, olefin polymer rubber, acrylic rubber, silicone rubber, and fluorine rubber. These synthetic rubbers may be used alone or in combination.

  Although content of rubber | gum (A) in the composition for film formation is not specifically limited, It is preferable that it is 45 to 80 mass% with respect to the total solid. If it is 45 mass% or more, it is preferable because the film formed on the surface of the structure becomes a film that is very easily stretched. If it is 80 mass% or less, since it is easy to adjust film quality by components other than (A) component, such as being easy to adjust the adhesive force of the film | membrane by polyvinyl alcohol (B), it is preferable. More preferably, the content of the component (A) is 50% by mass or more and 70% by mass or less. Most preferably, it is 51.2 mass% or more and 63.8 mass% or less.

[Polyvinyl alcohol (B)]
Polyvinyl alcohol (B) can be obtained by saponifying a polymer obtained by polymerizing polyvinyl acetate. Although the polymerization degree of (B) component is not specifically limited, It is preferable that it is 500-5000, More preferably, it is 500-3000. Moreover, it is preferable that the saponification degree of (B) component is 80 mol% or more and 99 mol% or less.

  Polyvinyl alcohol (B) is a component that imparts an adhesive force to the structure surface to the film. It is preferable that the adhesion strength of the film is strong in that the dirt on the surface of the structure is easily removed when the film is to be removed. On the other hand, if the adhesive force is too strong, it is difficult to peel off the film from the surface of the structure, and the film may be broken when the film is peeled off. For this reason, it is necessary to set suitably the kind of component (B), usage-amount, etc. according to the use of the composition for film formation.

  In addition, since polyvinyl alcohol (B) is a polymer that easily takes up water, when the content of component (B) increases, the film-forming composition is applied to the surface of the structure to form a coating film. It takes time to dry. In addition, since the component (B) tends to lower the strength of the film, if the content of the component (B) is too large, the strength of the film may be insufficient, and problems such as tearing of the film during peeling may occur. These problems are suppressed when the content of the rubber (A) contained in the film-forming composition is larger than that of the component (B).

  From the viewpoint of the drying property of the coating film applied using the film forming composition and the strength of the film formed by the film forming composition, the content ratio of the rubber (A) and the polyvinyl alcohol (B) is a mass ratio ( (B) / (A)) is preferably 0.01 or more and 0.3 or less. A more preferable mass ratio is 0.03 or more and 0.25 or less. The most preferable mass ratio is 0.036 or more and 0.2 or less.

  Thus, the combination of rubber (A) and polyvinyl alcohol (B) can impart strength and the like while imparting adhesiveness to the film. In order to adjust the strength and adhesiveness of the film in this manner, the main component of the film is preferably a combination of the component (A) and the component (B). The content of the component (A) relative to the total solid content of the film-forming composition and (B) so that the total of the content of the component (A) and the content of the component (B) in the film is a preferable amount. The total content of the components is preferably 60% by mass or more. More preferably, it is 60 mass% or more and 85 mass% or less.

  Moreover, when the content of polyvinyl alcohol (B) increases, the water resistance of the film decreases. From the viewpoint of imparting sufficient water resistance to the film, the content of the component (B) is preferably 15% by mass or less with respect to the total solid content.

  Moreover, when the pH of the film-forming composition is 10 or less, the polyvinyl alcohol (B) has a function of allowing the rubber (A) to exist stably in the composition. Specifically, the component (A) may solidify under acidity, but the component (B) surrounds the periphery of the component (A) in the composition, so that the component (A) is a film-forming composition. Can exist stably in. For example, when acidic clay described later is contained, the pH falls within the above range.

  Moreover, since polyvinyl alcohol (B) is a biodegradable material, if natural rubber is used as rubber (A), the film-forming composition of the present invention becomes a material with a very low environmental load.

[Water-insoluble powder (C)]
The film-forming composition of the present invention may contain a water-insoluble powder (C) in addition to the rubber (A) and the polyvinyl alcohol (B).

  By including the water-insoluble powder (C), the thickness of the film formed on the surface of the structure can be increased. When the film is thick, it is possible to increase the film strength by using the water-insoluble powder (C) such that the film is difficult to tear when the film is peeled off. Therefore, even if the amount of polyvinyl alcohol (B) used is increased to form a film having a strong adhesive force, it is possible to form a film that is difficult to tear at the time of peeling by using the water-insoluble powder (C). Moreover, since the viscosity of the film-forming composition is increased by including the water-insoluble powder (C), the water-insoluble powder (C) can be used for adjusting the viscosity of the film-forming composition.

  The water-insoluble powder (C) may be either an inorganic powder or an organic powder. Examples of the inorganic powder include anhydrous silicic acid, magnesium silicate, synthetic aluminum silicate, talc, kaolin, zeolite, zinc stearate, calcium carbonate, calcium lactate, activated carbon and the like. Examples of the organic powder include polymer particles such as polystyrene particles, polymethyl methacrylate particles, and silicone particles. However, (C) component is not limited to these, It can use 1 type or in combination of 2 or more types. Moreover, the particle size of (C) component is not specifically limited, However, As a standard, it is 1 micrometer or more and 100 micrometers or less.

  Since the water-insoluble powder (C) has a specific function, the film formed on the surface of the structure can be given a specific function. For example, when the water-insoluble powder (C) has a radioactive substance adsorbing ability, the film can more easily adhere the radioactive substance present on the surface of the structure.

  Examples of the water-insoluble powder (C) having the ability to adsorb radioactive substances include natural silica compounds such as acidic clay, cristobalite, montmorillonite, natural zeolite such as aluminosilicate, and clinoptilolite.

  The content of the water-insoluble powder (C) in the film-forming composition is not particularly limited and may be appropriately set according to the blending purpose of the component (C), but is 33% by mass with respect to the total solid content. It is preferable that it is 40 mass% or less.

[Surfactant (D)]
The film-forming composition of the present invention may contain a surfactant (D) in addition to the above essential components. By including the component (D), the stability of the rubber (A) and the water-insoluble powder (C) in the film-forming composition is increased. From the viewpoint of increasing the stability of the component (A) and the component (C) in the film-forming composition, the use of a nonionic surfactant is particularly preferable. In addition, you may use cationic surfactants and anionic surfactants other than a nonionic surfactant.

  The content of the surfactant (D) in the film-forming composition is not particularly limited, and may be appropriately determined according to the type and amount of rubber (A) or water-insoluble powder (C).

[Thickener (E)]
The film forming composition of the present invention may contain a thickener (E) in addition to the above essential components. By including the component (E), the viscosity of the film-forming composition can be adjusted without depending on the solid content in the film-forming composition. The ability to adjust the viscosity without depending on the solid content in the film-forming composition means that the viscosity of the film-forming composition can be adjusted independently of the film thickness. Therefore, the viscosity of the film-forming composition is not taken into account, and the thickener ((A) or polyvinyl alcohol (B) is adjusted by adjusting the amount of use, etc. If E) is used, the viscosity of the film-forming composition can be easily increased to a desired range.

  Although the kind of thickener (E) is not specifically limited, It is preferable to use thickening polysaccharide. Examples of the thickening polysaccharide include guar gum, locust bean gum, carrageenan, gum arabic, xanthan gum, gellan gum, curdlan, tamarind gum, psyllium seed gum, crystalline cellulose, modified starch, polydextrose and the like. These thickening polysaccharides may be used alone or in combination of two or more.

  The thickening polysaccharide is preferably used together with a water-soluble plasticizer in order to prevent the thickening polysaccharide from aggregating in the film-forming composition. Examples of water-soluble plasticizers include glycerin, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, tetramethylene glycol, pentamethylene glycol, hexamethylene glycol, 2,3-butanediol, and 1,3-butanediol. Etc.

  The content of the thickener (E) in the film-forming composition is not particularly limited, and may be set as appropriate according to the desired viscosity.

[Aqueous dispersion medium (F)]
The film-forming composition of the present invention is liquid and may be made liquid with components other than water, but is preferably made liquid with water. Since the film-forming composition becomes liquid in the presence of water, it is water, not a solvent, that evaporates when the coating film formed by coating the film-forming composition on the surface of the structure is water. It is preferable in terms of health and environment. In addition, alcohol etc. are mentioned as another aqueous dispersion medium (F).

  The content of the aqueous dispersion medium (F) in the film-forming composition is not particularly limited, but as the content of the aqueous dispersion medium (F) increases, the viscosity of the film-forming composition decreases. Moreover, when the content of the aqueous dispersion medium (F) in the film-forming composition increases, the solid content in the film-forming composition decreases. Therefore, what is necessary is just to set content of an aqueous dispersion medium (F) suitably, considering desired viscosity and solid content.

[Other ingredients]
The film-forming composition of the present invention may contain other components other than the above essential components and optional components as long as the effects of the present invention are not impaired.

[Method for producing film-forming composition]
The manufacturing method of the film forming composition of the present invention is not particularly limited, and for example, it can be manufactured by mixing necessary components. In mixing, ultrasonic treatment, stirring treatment, kneading treatment, and the like may be performed as necessary. For the stirring process and the kneading process, for example, a stirring or kneading apparatus such as a homogenizer, a spiral mixer, a planetary mixer, a disperser, or a hybrid mixer is used.

  A raw material in the form of an aqueous solution such as an aqueous solution of rubber (A) or an aqueous solution of polyvinyl alcohol (B) may be used. In particular, in the present invention, it is preferable to use natural rubber latex containing natural rubber as a raw material as the aqueous solution of rubber (A).

  Moreover, when manufacturing the composition for film formation containing a thickening polysaccharide, it is preferable to disperse | distribute a thickening polysaccharide in a water-soluble plasticizer first, and then to mix this with another component. This is because if this method is not employed, the thickening polysaccharide may aggregate in the film-forming composition.

[Physical properties of film-forming composition]
The viscosity of the film-forming composition is not particularly limited, but is preferably 30,000 mpa · s or less. If the viscosity is low, a film can be formed along the irregularities even if the surface of the structure to which the film-forming composition is applied has irregularities. The viscosity is measured in accordance with JIS K-7117: 1987 “Plastic—Liquid, Emulsion or Dispersed Resin—A Method for Measuring Apparent Viscosity Using a Rotational Viscometer”. The viscosity is measured at a liquid temperature of 25 ° C. and a rotor rotational speed of 6 rpm. The viscosity of the film forming composition is preferably 5,000 mp · s or more. If the viscosity is too low, the coating film applied to the surface of the structure may flow down and only a very thin film may be formed.

  Further, as described above, by using the water-insoluble powder (C) and the thickener (E), the viscosity can be adjusted without reducing the solid content in the film-forming composition. As described above, as a result of easy adjustment of the viscosity of the film-forming composition, the film-forming composition of the present invention can be preferably applied to the surface of various types of structures.

<Usage method of film forming composition>
The method of using the film forming composition of the present invention includes a film forming step of forming a film by applying the film forming composition of the present invention to at least a part of the surface of the structure.

[Structure]
The kind of structure is not particularly limited, and the film-forming composition of the present invention can be suitably applied to the surface of various structures. The material of the structure is not particularly limited. For example, glass, synthetic resin, aluminum and other metals, tile, earthenware, stoneware, earthenware, porcelain, wood, concrete, paper, rubber, fiber, stone material, earthen material, plaster, paint A film can also be formed on the surface of the structure finished with the above.

  The film forming composition of the present invention is characterized by containing the rubber (A) as described above, and water resistance is imparted to the film by containing the rubber (A). Therefore, a film can be preferably formed on the surface of an outdoor structure placed outdoors. Examples of outdoor structures placed outdoors include buildings, piers, tunnel inner surfaces, guardrails, utility poles, and the like.

[Film formation process]
In the film forming step, a film forming composition is applied to the surface of the structure to form a film. The method for forming the film is not particularly limited. For example, the film can be formed on the surface of the structure by the procedure shown in FIG.

  First, when a component is precipitated in the film-forming composition, stirring is performed to disperse the precipitated component in the film-forming composition. Next, this film forming composition is applied to the surface 2 a of the structure 2 to form the coating film 3. Here, FIG. 1 shows a state of roll coating, but the coating method is not particularly limited, and other conventionally known methods such as brush coating and spray coating can also be used. The film 4 can be formed by drying the coating film 3. The drying method is not particularly limited, and a dryer may be used, or drying may be performed by leaving it for a certain period of time.

  In the film-forming composition of the present invention, since the content of polyvinyl alcohol (B) is small, the moisture contained in the coating film is reduced and the time for drying the coating film is shortened. Therefore, if the film forming composition of the present invention is used, the film can be formed in a short time, and the work efficiency is increased. Further, since the rubber is contained in a large amount, the film itself is colored white, and the visibility of the film itself is excellent.

  The film 4 shown in FIG. 1 is a single layer. Even if it is a single layer, if the film forming composition of the present invention is used, sufficient strength can be imparted by the sufficient thickness of the film 4, the film 4 can be stretched, and the film 4 can be adhered to the surface of the structure 2. Since the property is also adjusted, the peeling process described later can be easily performed. In particular, the film has a thickness of 0.01 mm or more and 20 mm or less, and a degree of elongation at break measured under the conditions of JIS K-6251 is 150% or more and 1300% or less, preferably 300% or more and 900% or less. If it exists, it will be the film | membrane which has the adhesive force of the grade used preferably for the use mentioned later, and can peel very easily. The present invention is not limited to the case where the single-layer film 4 is formed, and other layers may be formed on the film 4.

[Peeling process]
Subsequently, as shown in FIG. 1, the film | membrane 4 is peeled as needed. At this time, for example, the dirt 1 moves from the surface 2a of the structure 2 where the dirt 1 such as foreign matter exists to the film 4 side, and the surface 2a can be cleaned. The adhesive force between the film 4 and the dirt is stronger than the adhesive force between the surface of the structure 2 and the dirt. For this reason, if a peeling process is performed and the film | membrane 4 is peeled from the surface 2a of the structure 2, the stain | pollution | contamination 1 will be pulled away from the surface of the structure 2 with the film | membrane 4. FIG. Thus, the film formed using the film forming composition of the present invention can be used for cleaning the surface of the structure 2. Moreover, since the film forming composition of the present invention can easily adjust the viscosity while setting the solid content in a desired range, a film along the unevenness of the surface of the structure 2 can be easily formed. Therefore, the dirt on the surface of the structure 2 can be removed as a whole. Moreover, since the film | membrane 4 has water resistance as above-mentioned, the composition for film formation of this invention can be used especially preferable for washing | cleaning of an outdoor structure. Even if the surface 2a of the structure 2 is uneven, the film 4 can be formed along the unevenness as shown in FIG.

  Further, when a radioactive substance is present on the surface of the structure 2, the film 4 and the radioactive substance are bonded. For this reason, the radioactive substance which exists in the surface of the structure 2 is removed by performing the peeling process mentioned later. In particular, when the water-insoluble powder (C) having the radioactive substance adsorption ability is contained in the film-forming composition 1, the amount of the radioactive substance that adheres to the film 4 increases and exists on the surface of the structure 2 The removal efficiency of the radioactive material to increase. Moreover, since the film | membrane 4 is formed along an unevenness | corrugation, a radioactive substance can be removed all over.

  By the way, even when a radioactive substance exists on the ground surface, it is required to remove the radioactive substance. In such a case, the radioactive substance can be removed by forming a film on the ground surface using the film forming composition of the present invention and peeling the film.

  Furthermore, the film 4 can be preferably used as a temporary sealing film. For example, the water resistance of the membrane 4 can be utilized to be used as a waterproof membrane. Further, it can be used as a protective film for protecting the surface of the structure 2 from being contaminated during the work on the structure 2.

  In particular, in the case of work such as construction, it is often necessary to temporarily protect the ground surface. Therefore, in such a case, the film forming composition of the present invention can be preferably used.

  In some cases, the film 4 formed on the surface of the structure 2 is not peeled off. For example, when the film 4 is used as a protective film, it can be preferably used even when the film is not peeled after the necessity of protection is lost. In this case, if it is a natural rubber component, it will decompose naturally. As described above, since the film-forming composition of the present invention is composed of a material having a small environmental load, even if the film 4 is not peeled in this way, the film 4 has an adverse effect on the environment. almost none.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, this invention is not limited to the Example shown below at all.

<Material>
(A) Natural rubber latex: solid content of 62% by mass, molecular weight distributed in the range of 10,000 to 2,000,000 (manufactured by Regex Corporation, “HANR-LATEX”)
(B) Polyvinyl alcohol aqueous solution: An aqueous solution containing 25% by mass of polyvinyl alcohol. Polyvinyl alcohol has a saponification degree of 80 to 84% and a polymerization degree of 500 to 700 (“JL-05E” manufactured by Nihon Acetate / Poval).
(C) Calcium carbonate (C2) Acid clay

<Example 1>
A film forming composition was prepared by mixing 55% by mass of natural rubber latex, 5% by mass of an aqueous polyvinyl alcohol solution, 15% by mass of calcium carbonate, 3% by mass of acid clay, and 22% by mass of water (mass of polyvinyl alcohol / rubber). The ratio is 0.091, and the total mass ratio of rubber and polyvinyl alcohol in the total solid content is 0.037%). The film-forming composition was applied to the surface of a glass plate to form a coating film on the surface, and the coating film was dried to form a film (0.5 to 1 mm). The film was formed along the irregularities on the surface. Moreover, the film could be easily peeled off from the surface of the glass plate. Table 1 shows the viscosity of the film-forming composition, the solid content in the film-forming composition, the stress at break of the film, the elongation at break, and the degree of elongation at break (the length of the film before the tensile test was 100%. When the film was broken in the tensile test, the film length (%)) and the peel strength were shown. The methods for deriving the stress at break, elongation at break, elongation at break, and peel strength are as follows.

  A JIS No. 4 dumbbell test piece was cut out from the membrane of Example 1. Using a tensile tester, the stress at break, the elongation at break, and the degree of elongation at break were derived under the conditions according to JIS K6251 and the tensile speed of 500 mm / min.

The film-forming composition used in Example 1 above was applied to a canvas having a length of 350 mm, overlapped in the longitudinal direction on a plywood board having a thickness of 20 mm, a width of 50 mm, and a length of 150 mm, and dried for a day to form a canvas and a plywood board. Bonded (the bonding area between the veneer and the canvas was 37.5 mm ² ). Peel strength (kg) was derived under the conditions of 23 ° C., 180 ° C. peeling, and tensile speed of 300 mm / min by the method according to JIS K6854-2 using an adhesive material between the canvas and the plywood as a test piece.

<Comparative Example 1>
After a polyvinyl alcohol aqueous solution, which is a film-forming composition, is applied to the surface of a glass plate, a nonwoven fabric is immediately placed on the glass plate, and the same polyvinyl alcohol aqueous solution is applied to the nonwoven fabric. A multilayer film of polyvinyl alcohol containing was formed on the surface of the glass plate. The thickness of the multilayer film was about 0.4 mm. Table 1 shows the viscosity of the film-forming composition, the solid content in the film-forming composition, the stress at break, the elongation at break, the degree of elongation at break, and the peel strength.

  From Table 1, it is considered that the films of the examples were easily stretched and could be easily peeled because the adhesive strength of the films was also adjusted. Further, in the examples, even if the viscosity of the film-forming composition was adjusted, the solid content could be increased, so that a thick film could be formed even if the coating area was increased. Moreover, in an Example, since there is little quantity of the polyvinyl alcohol contained in a film | membrane, it becomes a film | membrane excellent in water resistance.

<Examples 2 to 4, Reference Examples 1 and 2, Comparative Example 2>
The components shown in Table 2 were mixed in the proportions shown in Table 2 (unit: mass%) to produce a film-forming composition (Note that Table 3 shows the content of each component with respect to the total solid content) Unit is mass%)). The film-forming composition is applied to the surface of a PET plate to form a coating film, and the coating film is dried to form a film. The stability of the film-forming composition, the film elongation, the film peeling property, The results of evaluating the water resistance of the membrane are shown in Table 2.

※凝固のため製膜できず

* No film formation due to coagulation

  From Table 2, it was confirmed that the film can be easily peeled while imparting adhesiveness by considering the amount of rubber, the amount of polyvinyl alcohol, and the solid content in the film-forming composition. Moreover, any film | membrane has high water resistance, and especially the film | membrane of Examples 2-3 has very high water resistance. In Comparative Examples 3 and 4, it can be considered that there is a possibility of higher evaluation if the solid content is adjusted to make the film thicker or multilayered.

<Example 7>
The dose equivalent rate (μSv / h) and surface contamination density (Kcpm) of the surface of the decontamination object (concrete) were measured. The results are shown in Table 4.

  The film forming composition of Example 1 was applied to the concrete surface to form a coating film, and this coating film was dried to form a film having the same dry film thickness as that of Example 1. Then, the membrane was peeled from the surface and collected.

  The dose equivalent rate (μSv / h) and surface contamination density (Kcpm) of the surface of the concrete after the film was peeled were measured. The results are shown in Table 4. The decontamination rate was calculated from this result and the result before film formation.

  From Table 4, it was confirmed that the film | membrane formed with the film forming composition of this invention can be used conveniently for removal of a radioactive substance.

DESCRIPTION OF SYMBOLS 1 Dirt 2 Structure 2a Surface 3 Coating film 4 Film

Claims (13)

It is a liquid containing rubber (A) , polyvinyl alcohol (B) , and inorganic water-insoluble powder (C) ,
The content ratio of the rubber (A) and the polyvinyl alcohol (B) is 0.01 to 0.3 in terms of mass ratio ((B) / (A)),
A film-forming composition for cleaning, which is peeled after a temporary surface protective film is formed on the structure surface and / or the ground surface . The film-forming composition according to claim 1, wherein the total content of the rubber (A) and the polyvinyl alcohol (B) is 60% by mass or more based on the total solid content. The film-forming composition according to claim 1 or 2, wherein the rubber (A) is natural rubber. The film forming composition according to any one of claims 1 to 3 , comprising a natural rubber latex. The water-insoluble powder (C) is a powder having a radioactive substance adsorption ability , and is at least one selected from acidic clay, cristobalite, natural silica compound, aluminosilicate, and natural zeolite. 5. The film forming composition according to any one of 1 to 4 . The film-forming composition according to any one of claims 1 to 5 , which is used for cleaning the surface of a structure. The film-forming composition according to any one of claims 1 to 5 , which is used for removing radioactive substances present on the structure surface and / or the ground surface. A film forming step of forming a temporary film composition for film formation according to any one of claims 1 to 5 is applied to the structure surface, the surface cleaning method and a separation step of separating the membrane. The surface cleaning method according to claim 8 , wherein in the film forming step, the film is formed as a single layer. The surface cleaning method according to claim 8, which is applied to surface cleaning of an outdoor structure. A film forming step of forming a temporary film by applying the film forming composition according to any one of claims 1 to 5 to a structure surface and / or a ground surface, and a peeling step of peeling the film. A radioactive substance removing method provided. A surface protection method for forming a temporary surface protective film by applying the film-forming composition according to any one of claims 1 to 5 to a structure surface and / or a ground surface. Containing rubber (A), polyvinyl alcohol (B) and inorganic water-insoluble powder (C) ;
The content ratio of the rubber (A) and the polyvinyl alcohol (B) is 0.01 to 0.3 in terms of mass ratio ((B) / (A)),
A cleaning film that peels off after a temporary surface protection film is formed on the surface of the structure and / or the ground surface ,
The film | membrane whose thickness of the said film is 0.01 mm or more and 20 mm or less, and whose elongation at break measured by the method based on JISK-6251 is 150% or more and 1300% or less.

Images